Handle slow/lossy connections better when sending transactions

1 files changed, 11 insertions, 5 deletions

diff --git a/synapse/federation/transaction_queue.py b/synapse/federation/transaction_queue.py

index a4e760f935..2f70a148e9 100644
--- a/synapse/federation/transaction_queue.py
+++ b/synapse/federation/transaction_queue.py
@@ -455,16 +455,22 @@ class TransactionQueue(object):
                 pending_pdus = self.pending_pdus_by_dest.pop(destination, [])
 
                 # We can only include at most 50 PDUs per transactions
-                pending_pdus, leftover_pdus = pending_pdus[:50], pending_pdus[50:]
+                pending_pdus, leftover_pdus = pending_pdus[-5:], pending_pdus[:-5]
                 if leftover_pdus:
-                    self.pending_pdus_by_dest[destination] = leftover_pdus
+                    # self.pending_pdus_by_dest[destination] = leftover_pdus
+                    for _, _, p_span in leftover_pdus:
+                        p_span.set_tag("success", False)
+                        p_span.log_kv({"result": "dropped"})
+                        p_span.finish()
+
+                logger.info("TX [%s] Sending PDUs: %s", destination, pending_pdus)
 
                 pending_edus = self.pending_edus_by_dest.pop(destination, [])
 
                 # We can only include at most 100 EDUs per transactions
-                pending_edus, leftover_edus = pending_edus[:100], pending_edus[100:]
-                if leftover_edus:
-                    self.pending_edus_by_dest[destination] = leftover_edus
+                pending_edus, leftover_edus = pending_edus[-5:], pending_edus[:-5]
+                # if leftover_edus:
+                #     self.pending_edus_by_dest[destination] = leftover_edus
 
                 pending_presence = self.pending_presence_by_dest.pop(destination, {})